The "Firefly" star has joined The CW's breakout hit as a "dangerous" new addition.

Arrow is adding a fierce female with major geek cred to the mix for season two.

Firefly and Terminator: The Sarah Connor Chronicles star Summer Glau has booked a recurring role on The CW's breakout action drama toplined by Stephen Amell, The Hollywood Reporter has learned.

Glau will play the "enigmatically beautiful" and "dangerous" Isabel Rochev, vp acquisitions at Stellmoor International, a company looking to take over Queen Consolidated. She will first appear in the premiere.

On Arrow, not much is known of Isabel, except as part of a list of names in Robert Queen's book of corrupt and powerful people in Starling City. (In the DC Comics universe, the villainous Isabel — who appears in several Green Arrow issues — rose from being a slave to running Queen Industries, with the desire to return the company back to its former glory.)

Arrow will be hitting San Diego's Comic-Con for the second year on Saturday, July 20, from 5:15-6 p.m. to preview the new season with executive producers Greg Berlanti, Marc Guggenheim and Andrew Kreisberg, as well as castmembers Amell, Katie Cassidy, Colton Haynes, Emily Bett Rickards and David Ramsey. (Haynes, Rickards and Bennett were promoted to series-regular status for season two.)

Glau, repped by UTA and The Schiff Co., starred as River Tam in cult favorites Firefly and Serenity. Other notable credits include Dollhouse, The Cape, Alphas, The 4400, Grey's Anatomy, Chuck and The Big Bang Theory.

The CW has released the first promo images for the upcoming mid-season premiere of "Arrow" which you can check out by clicking here or on the images below. Titled "Blast Radius," the episode is described as follows:

"Oliver must tackle a new threat to the city when bombs start to go off in Starling City. Felicity discovers the person setting them off is Mark Sheffner (guest star Sean Maher), a man who goes by the nickname Shrapnel. Arrow discovers Shrapnel�s next target is Sebastian Blood�s (guest star Kevin Alejandro) �Unity Rally� and tries to talk the alderman out of hosting it, but he refuses. Arrow sets off to stop the bombing, but Shrapnel tricks him and traps him in a bomb-laced antique store where he is unable to move without setting off the device. While Felicity helps Oliver, Diggle races to the plaza to find the bomb before it goes off. Meanwhile, Roy continues to hide his new strength from Thea but, after she witnesses his super strength in action at the rally, she demands answers. Laurel�s suspicions about Sebastian grow stronger once she learns that he grew up with Cyrus Gold, the man who killed Lance�s partner. After Donner (guest Star Dylan Bruce) refuses to help her investigate, she turns to Arrow for help."

Directed by Rob Hardy and written by Jake Coburn & Keto Shimizu, the episode will premiere on January 15th. "Arrow" airs on Wednesdays at 8 P.M. ET/PT on The CW.